Unraveling Hydrogen Sulfide Detection and Lysosome-Mitochondria Fusion in Mitophagy Using Dual Phenothiazine-based Fluorescence Probes

Mitophagy is a critical cellular self-protective mechanism involving the degradation and recycling of damaged or excessive mitochondria, which has been implicated in various diseases. In our study, we designed and synthesized two phenothiazine-based fluorescent probes, DPTZ and CMDP, specifically targeting mitochondria and lysosomes, respectively, to investigate mitophagy. H2S, a cell-protective agent, was chosen as the target molecule for both probes. Our findings demonstrate the selective localization of DPTZ to mitochondria and CMDP to lysosomes. Both probes exhibited rapid, selective, and highly sensitive recognition of H2S, enabling imaging of exogenous and endogenous H2S. By employing split-targeting and simultaneous detection, we were able to monitor changes in H2S levels in mitochondria and lysosomes, providing dynamic and visual imaging of the mitophagy processes. Upregulation of mitochondrial and lysosomal H2S was observed during mitochondrial autophagy. This work introduces valuable research methods and tools for investigating mitophagy, thereby enhancing our understanding of the molecular mechanisms underlying this process.